Device for facilitating the starting of refrigerating apparatus of the compressor type



July 4, 1939. R. HINTZE 2,164,405

DEVICE FOR FACILITATING 'I 'HE STARTING OF REFRIGERATING APPARATUS OFTHE COMPRESSOR TYPE Filed Aug. 20, 1937 2 Sheets- -Sheet 1 July 4, L939;R. HINTZE 2 I DEVICE FOR FACILITATING THE STARTING 0F RBFRIGERATINGAPPARATUS OF THE COMPRESSOR TYPE Filed Aug. 20, 1957 2 Sheets-Sheet 2.;

Search UNITED STATES PATENT OFFICE DEVICE FOR FACILITATING THE STARTINGOF REFRIGERATING APPARATUS OF THE COMPRESSOR TYPE Rudolf Hintze,Berlin-Charlottenburg, Germany,

assignor to Siemens-Schuckertwerke Aktiengesellschaft,Berlin-Siemensstadt, Germany, a corporation of Germany ApplicationAugust 20, 1937, Serial No. 160,011 In Germany August 26, 1936 14Claims.

My invention relates to compressors, and more particularly tocompressors in refrigerating systems.

In refrigerating apparatus of the compressor type, particularlyelectrically-operated units, it is known to provide means for unloadingthe motor when starting and when operating it at low speeds. To thisend, in general, a conduit connecting the suction side of the compressorwith the pressure side is opened when the unit is at rest or is operatedat low speeds, and this conduit is closed by a valve only upon theattainment of higher speeds. For controlling this valve, means havehitherto been employed which are dependent upon the centrifugal force.Furthermore, it is known to operate such valves electromagneticallyor inaccordance with the pressure of the refrigerant or of the lubricatingoil contained in the apparatus. My invention concerns devices of thelast-mentioned type in which a valve is employed which operates inresponse to the oil pressure and upon exceeding a given pressure closesa conduit connecting the suction side with the pressure side of thecompressor.

An object of my invention is to improve the construction of devices ofthe above-mentioned kind by closely associating the lubricating pumpwith the means for operating the unloading valve of the compressor. Moreparticularly, while in the controls hitherto known, operating inresponse to the oil pressure, two very accurate running fits arenecessary, 1. e., one for the oil pump and the other for the valve, anobject of the invention is to necessitate only one running fit.

Other objects of my invention concern an improved operation of thecompressor arrangements above referred to. In this respect, moreparticularly an object is to obtain a reliable re-' sponse of theunloader device even if the forces available for operating the unloaderare relatively small. Anobject in this line, further, is to diminish theimpeding influence of foreign substances in the lubricant on theaccuracy and reliability of operation.

A further object is the simplification and spacial contraction of thecompressor pump, and unloader arrangement, as well as a space-savingadaptation of such arrangements to a refrigerating system in which theentire arrangement is sealed in a common container which is connected inthe circulating system of the refrigerant.

An object, particularly in connection with one or more of the precedingobjects, is to provide means for preventing an increase in the pressureof the lubricant above a certain maximum value.

According to my invention the lubricating pump of acompressorarrangement of the abovementioned type is kinematically associated withthe unloader device of the compressor so that the unloader is directlyactuated by means of a mechanical connection with the pump. In carryingthe invention into practice a rotary oil pump is preferably employedwhich has one of the cooperating pumping members arranged so as to beshiftable in the axial direction responsive to the oil pressure, theaxial movement being employed to operate the unloader. Since the activepumping members of the pump revolve relatively to each other when theshiftable member is axially displaced, the two members perform spiralmovements with respect to each other so that a very fine regulation isattained even if the controlling forces are comparatively small. Incontradistinction thereto, the actuating member of the known valvecontrols, which are displaced responsive to the oil pressure, efi'ectonly a straight relative motion so that considerably greater controllingforces must be produced, especially in the event of slight amounts offoreign substances, such as dirt, being present between the movableparts.

Further objects and details of the invention will become apparent fromthe following description of the two embodiments illustrated in thedrawings in diagrammatic form.

Fig. 1 shows a sectional view of the lower part of the compressor casingof a motor-driven refrigerating apparatus of the compressor type.

Fig. 2 is a perspective view of the novel oil pump at rest shown in Fig.1.

Fig. 3 is a perspective view of the oil pump in operating position.

Fig. 4 shows a modified form of the invention.

Referring to Fig. 1, I denotes the lower portion of the compressorcasing. Within the cylinder 2 connected to the casing is mounted apiston 3. The crank shaft 6 with the crank 5 serves to drive the piston.The refrigerant passes from the evaporator, not shown, through conduit 4into the gas chamber I of the compressor and, by the action of thepiston, is sucked into the cylinder 2 through the passage 8. After beingcompressed, the refrigerant passes through the opening 9 of thespring-biased valve l0 into the pressure conduit ll of the refrigeratingapparatus. The lubricant I2 is collected in the Room lower part of thecompressor casing I and is supplied by an oil pump secured to the lowerend of the crank to the points of the apparatus to be lubricated.

The oil pump has two cooperating pumping members I3 and I4 arrangedcoaxially to the crank shaft 6. Member I3 is revolvable and connectedwith crank 5 so as to be operated simultaneously with the operation ofthe compressor. The second pumping member I4 is arranged within themember I3 and is axially displaceable against member I3. A lever 26passing through a recess in the lower end of member I4 prevents thismember from revolving. The non-revolvable inner member I4 which fitsaccurately into the cylindrical boring 6| of the rotary member I3 hashelical threads 62 the lower end of which forms an entrance opening I5for the lubricant to be impelled by the pump. The upper end of thethread opens into a passage |6 which is connected with an annular space64. Ducts I1 and I8 in the crank connect the space 64 with the places ofthe apparatus to be lubricated.

The lever 20 securing the member I3 against rotation is linked to aU-shaped lever I9 as indicated at 2|. The lever I9 is pivoted at 22 onan arm 23 which is secured to the stationary cylinder. The stationarymember I4 of the oil pump may carry out an axial movement in thevertical direction while moving the levers 20 and I9 downward. 25denotes the needle of a valve which in the position shown is moved awayfrom the valve seat 26 and which, therefore, opens a conduit 21connecting the suction side and the pressure side of the compressor whenthe apparatus is at rest and at low speeds. The valve needle 25 isslidably arranged in a sleeve 28. One end of the sleeve 28 contacts witha nose 24 of the lever I9. To the valve needle '25 is firmly secured aholder 29, a controlling spring 30 en-' gaging one side of the holder 29and a second spring 3| engaging the other side thereof. These springstend to hold through levers I9 and 20 the pumping member I4 in raisedposition.

The oil pump and the valve combined therewith operate as follows:-

When starting the compressor, the outer pumping member I3 is rotatedagainst the inner member I4. The oil near the cylindrical boring 6| ofmember I3, impelled by this rotation, is pressed upward through thethread windings 62 into the duct I6 and the annular space 64 whence itreaches the different points to be lubricated. At the beginning of thisoperation, the springs 30 and 3| are in expanded condition and thelevers I9 and 20, as well as the member I4, are in the raised positionshown in the figure. The valve needle 25, therefore, also assumes theposition illustrated in which the compressor is unloaded. However, thepumping effect produced by members I3 and I4 causes an increase ofpressure in the annular space 64. This increasing pressure now forcesthe member I4 downward, thereby rotating the lever I9 in clockwisedirection so that the nose 24 of lever I9 presses against the sleeve 28thus moving the needle 25 in the closing direction of the valve againstthe force of spring 30. When the oil pressure becomes great enough toovercome this counter-force, the valve is closed and the compressorfully loaded. The force of the spring 36 is so rated that the valve isclosed only after the starting period of the refrigerating apparatus isfinished so that normal operating conditions prevail.

In order to prevent an unduly high pressure, a relief port 32 isprovided in the revolvingmember I3 of the pump. As soon as the oilpressure has increased to such an extent as to cause the valve seat 26to be closed, the axially displaceable member I4 of the pump maycontinue its movement in the downward direction, since then the lever |9displaces the sleeve 29 relatively to the valve needle 25 against theforce of the spring 3|. Upon further displacement of member I4relatively to member I3 of the pump, the port 32 is uncovered so thatpart of the oil in space 64 is discharged through the port.

In the modified form of the invention illustrated in Fig. 4, 4| denotesthe compressor casing of the refrigerating apparatus, 42 is the cylinderand 43 the piston which is driven by the electric motor 46 through thecrank 45. The motor 46 is resiliently supported on the compressor casing4| through springs 40. The refrigerant is drawn in by the compressorthrough the conduit 41 and passes through the port 59 into the cylinder42, whence the compressed refrigerant is supplied to the condenser (notshown) through the valve 48 and the conduit 49. The lower end 65 of theshaft 66 of the driving motor 46 extending through the casing 61 thereofis designed as one of the two pumping members of an oil pump of the sametype as described in the foregoing with reference to Figs. 1, 2 and 3.To this end, the lower end 65 of the shaft is threaded, as indicated by66, and is enclosed by a sleeve 5| which forms the second member of thepump. A lever 53 pivoted at 54 to a stationary arm 50 secures thepumping member 5| against rotation but allows the member to be displacedin the downward direction against the force of a spring 52 upon anincrease of the oil pressure acting in the space 69. The lever 53 iscoupled through a spring 51 with a valve rod 55 controlling a reliefvalve 56.

The function of this modification is in principle the same as that ofthe preceding embodi-r ment. Upon an increase of the oil pressure, themember 5| of the pump is forced downward against the action of spring 52and causes the rod 55 to close the valve 56 so that the'compressor isfully loaded only after a certain starting period. When the valve 56 hasbeen closed, the sleeve 5| may continue to move in the downwarddirection while compressing the spring 51. In this manner an oil reliefport 56 is opened upon the attainment of a given oil pressure.

I claim as my invention:

1. In a compressor arrangement, in particular for refrigerating systems,having a lubrication pump coupled with the compressor and a device forunloading said compressor in dependence upon the pressure of thelubricant produced by said pump, said pump having two cooperativepumping members arranged movably with relation to each other anddesigned to impel said lubricant by said relative movement, one of saidpumping members being arranged so as to be additionally movable in adirection differing from that of said first movement in response to theincrease in the pressure of said lubricant caused by said pump, and amechanical connection between said additionally movable pumping memberand said unloading device for operating said device by said additionalmovements of said latter member.

2. In a compressor arrangement, in particular guy/we,

for refrigerating system, having a lubricatim pump coupled with thecompressor and a device for unloading said' compressor in dependenceupon the pressure of the lubricant Produced by said pump, said pumphaving a revolvable pumping member for impelling said lubricant, saidmember being arranged to be displaceable in axial direction responsiveto the pressure of said lubricant, and a mechanical connection betweensaid member and said unloading device for operating said device by saidaxial displacements of said member.

3. In a compressor arrangement, in particular for refrigerating systems,having a lubrication pump coupled with the compressor and a valve forunloading said compressor at low operating speeds, arranged between thepressure side and the suction side of said compressor, said pump havingtwo cooperative pumping members revolvable with relation to each otherand designed to impel the lubricant by said revolution, one of saidpumping members being arranged so as to be displaceable in axialdirection responsive to the pressure of said lubricant produced by saidpump, and a mechanical connection between said displaceable member andsaid valve for operating said valve by said displacements of said lattermember.

4. In a compressor arrangement, in particular for refrigerating systems,having a lubrication pump coupled with the compressor and a device forunloading said compressor in dependence upon the pressure of thelubricant produced by said pump, said pump having two cooperativepumping members, one of said members being revolvable for impelling saidlubricant, the other of said members being displaceable in axialdirection responsive to the pressure of said lubricant, and a mechanicalconnection between said displaceable member and said unloading devicefor operating said device by the displacements of said latter member.

5. In a compressor arrangement, in particular for refrigerating systems,having a lubrication pump coupled with the compressor and a valve forunloading said compressor at low operating speeds, arranged between thepressure side and the suction side of said compressor, said pump havingtwo cooperative pumping members revolvable with relation to each otherand designed to impel the lubricant by said revolution, one of saidpumping members being arranged so as to be displaceable in axialdirection responsive to the pressure of said lubricant produced by saidpump, a mechanical connection between said displaceable member and saidvalve for operating said valve by said displacements of said lattermember, and spring means tending to maintain said displaceable member invalve opening position.

6.- In a compressor arrangement, in particular for refrigeratingsystems, comprising a lubrication pump coupled with the compressor andhaving a pressure relief port designed to be normally closed, said pumphaving two cooperative pumping members revolvable with relation to eachother and designed to impel the lubricant by said revolution, one ofsaid pumping members being arranged so as to be displaceable in axialdirection responsive to the pressure of said lubricant and designed toopen said pressure relief port of said pump upon reaching a givenmaximum displacement, a valve for unloading said compressor at lowpressure of said lubricant, a mechanical connection between saiddisplace- Search Room able member and said valve for closing said valveby displacements smaller than said maximum displacement, a springassociated with said connection and tending to maintain saiddisplaceable member in valve opening position, and a second springarranged so as to impede the further displacement of said latter memberwhen said valve is in closed position.

'7. In. a compressor arrangement, in particular for refrigeratingsystems, comprising a lubrication pump coupled with the compressor andhaving relief means for limiting the pressure of the lubricant, and avalve for unloading said compressor at low pressure of said lubricant,said pump having two cooperative pumping members revolvable withrelation to each other and designed to impel said lubricant by saidrevolution, one of said pumping members being arranged so as to bedisplaceable in axial direction responsive to the pressure of saidlubricant and designed to be integral with said relief means, and amechanical connection between said displaceable member and said valvefor operating said valve by said displacements of said latter member.

8. In a compressor arrangement, in particular for refrigerating systems,comprising a lubrication pump coupled with the compressor and having apressure relief port designed to be normally closed, and a valve forunloading said compressor at low pressure of the lubricant, said pumphaving two cooperative pumping members revolvable with relation to eachother and designed to impel said lubricant by said revolution, one ofsaid pumping members being arranged so as to be displaceable in axialdirection responsive to the pressure of said lubricant and designed toopen said pressure relief port of said pump upon' reaching a givenmaximum displacement, and a mechanical connection between saiddisplaceable member and said valve for closing said valve bydisplacements smaller than said maximum displacement.

9. With a compressor, in particular for refrigerating systems, incombination, means for unloading said compressor, a lubrication pumphaving two cooperative cylindrical pumping members having the form of abolt and of a cup surrounding said bolt, respectively, and beingrevolvable and axially displaceable relatively to each other, one ofsaid pumping members having helical threads forming a passage for thelubricant to be impelled through said threads by the relative revolutionof said members, a duct for said lubricant connecting said passage withthe end face of said bolt-shaped member in order to axially displacesaid members relatively to each other responsive to the pressure of thelubricant, a mechanical connection between said ump and said unloadingmeans of said compressor for operating said unloading means by saidaxial displacements, and resilient means arranged to counteract saiddisplacements and tending to maintain said members in a position whereinsaid compressor is unloaded.

10. With a compressor, in particular for refrigerating systems, incombintion, means for unloading said compressor, a lubrication pumphaving two cooperative cylindrical pumping members having the form of abolt and of a cup surrounding said bolt, respectively, and beingrevolvable and axially displaceable relatively to each other, one ofsaid pumping members having helical threads forming a passage for thelubricant to be impelled through said threads by the relative revolutionof said members, a

duct for said lubricant connecting said passage with the end face ofsaid bolt-shaped member in order to axially displace said membersrelatively toeach other responsive to the pressure of the lubricant, amechanical connection between said pump and said unloading means of saidcompressor for operating said unloading means by said axialdisplacements, a pressure relief port arranged in said cup-shaped memberspaced apart from the bottom face of said cup so as to vent said ductwhen said displacements exceed a maximum distance, and resilient meansarranged to counteract said displacements and tending to maintain saidmembers in a position wherein said compressor is unloaded and saidrelief port closed.

11. With a compressor, in particular in a refrigerating system, thecombination of a rotatable driving element connected with saidcompressor, said driving element having a duct for passing a lubricantto said compressor, a lubricating pump connected with said drivingelement so as to communicate with said duct, said pump having twocooperative pumping members, one of said members being'rotatable andconnected with said driving element, the other of said pumping membersbeing axially displaceable in response to the pressure of said lubricantin said pump, and a. valve for unloading said compressor, said valvebeing mechanically connected with said displaceable member so as to beoperated by the displacements of said latter member.

12. With a compressor, in particular in a refrigerating system,thecombination of a crank for actuating said compressor having a crankarm provided with a duct for the passage of a lubricant, a rotarylubricating pump communicating with said duct and having two coaxialpumping members, the outer of said members forming a rotary sleeve andbeing coupled with said crank arm, the inner of said pumping membersbeing axially displaceable responsive to the pressure of said lubricant,a valve for unloadingsaid compressor, a connection between said innerpumping member and said valve for operating said valve by thedisplacements of said lattermember, and spring means tending to maintainsaid latter member and said connection in valve opening position.

13. With a compressor, in particular in a refrigerating system, thecombination of a motor for driving said compressor, said motor having ashaft provided with a longitudinal duct for the passage of a lubricant,a lubricating pump coaxial to said shaft and communicating with saidduct, said pump having two coaxial pumping members, one of said membersbeing associated with said shaft, the other of said members beingaxially displaceable responsive to the pressure of said lubricant, avalve for unloading said compressor, a connection between saiddisplaceable pumping member and said valve, and spring means tending tomaintain said valve and said displaceable member in valve openingposition.

14. With a compressor, in particular for refrigerators, having ahorizontal cylinder and a reciprocatory piston disposed in saidcylinder, and a crank mechanism having a vertical crank shaft and acrank pin for reciprocating said piston, in combination, a lubricatingsystem comprising a container for collecting the lubricant, alubrication pump comprising two cooperative pumping members, one of saidpumping members consisting of a bolt arranged coaxially with respect tosaid crank shaft, said other pumping member consisting of a sleeverevolvable about said bolt, one of said pumping members having a helicalthread in its surface contacting said other member so as to form ahelical passage for the lubricant, the intake of said helical passagebeing submerged in said collected lubricant when in operation, and saidcrank pin being connected with said sleeve for revolving said sleeve.

RUDOLF' HmTZE.

